题目内容
13.Explorer Roberthad searched (search) for the Titanic for 20 years before he found it.分析 探索者Robert在找到它之前已经搜寻泰坦尼克号二十年了.
解答 答案:had searched
解析:"找到它"是一般过去时,故根据句意"找到它之前已经搜寻泰坦尼克号二十年了"可知前面的主句该使用过去完成时(过去的过去使用过去完成时);又因为Robert与"搜寻"之间是主谓(主动)关系,故本题答案为had searched.
点评 本题考查单词填空,做此类题目时一定要仔细分析句子结构,根据所给词从语法、句意、时态等各方面判断所填词的正确形式.
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